Piston



March 4 1924. V 1,486,110

' W. HACK PISTON 1 Filed June 5, 1922 INVENTOR Cars a e/v ings,

Patented Mar. 4, I

UNITED STATES.

PATENT OFFICE},

CHARLES W. BACK, OF 'IOI'EKA, KANSAS, ASSIGN'OR TO THE HOME BIE1]?RIGIliZRA'J3IIN'G COMYANY, OF TOPEKA, KANSAS, A CORBORATION OF KANSAS.

- rrsron.

Application filed June 5, 1922. Serial 1101561827.

To all whom it may concern. 1

Be it known that 1, CHARLES W. HACK, a citizen of the United States, residin at Topeka, in the county of Shawnee and tate of Kansas, have invented .certain new and useful Improvements in Pistons; and I do declare the following to be a full, clear, and exact description of the invention, such it appertains to make and use the same, reference being had to the accompanying drawthereon, which form a part of this specification.

This invention relates to a novel means for confining compressible fluid in the combustion chamber of a cylinder and the invention particularly contemplates an improvement in compressors.

It is the purpose of the invention to rovide a. cylinder and piston which wil be so co-related that liabi 'ty of leakage of the gas or compressible fluid" past the piston will be reduced to a minimum if not entirely eliminated.

Pistons are usually ofmetal and they are rovided with packing rings which more or ess serve the purpose intended. The lubrication of the piston with respect to the ctvlla ie The met inder is always a problem. piston rings, too, have a tendenc to score the cylinders and they frequently ave to be replaced.

I have found that highly satisfactory results can be obtained by providing a lston having as a com onent art thereof ubricant absorbing er an I prefer to construct the piston of a non-metallic substance. The fiber can be, though not necessarily for all purposes, arranged in the form of sheets so that the edges of the sheets will have rubbing contact against the cylinder to polish it, the fabric and non-metallic substance eliminating the possibilit of scoring the cylinder. The ends of t e' fibers are exposed at the surface of the piston so that they constitute lubricant-absorbin means, the fiber being adapted to be supp 'ed with a lubricant in grooves in the piston; that is, the lubricant can be spread over the surface of the cylinder to be taken up by the capillary attraction of the fiber and reapphed to the cylinder surface as the piston reciprocates over it.

aswill enable others skilled in the art to which and to the figures of reference marked- The piston is referably formed of a material having su stantially the same co-eflicient of expansion as the cylinder and that materials admirably adapted for the purpose are substances known commercially as micarta and bakelite, with which the fiber is combined, although the fiber may be embedded in metal. The substances known as -micarta and bakelite, as is well known, are formed under high pressures, and where they are used, the fabric may be cotton, hemp, wood fiber or any suitable material. Where'the fiber is to be combined with the metal, asbestos is recommended.

The piston thus formed, if machined to a true t, efliciently seals the cylinder; has a tendency to polish the surface due, it is be lieved, to the fiber present as well as the characteristics of the embedding material;

and eflicientl lubricates the same.

Actually cylinder with a novel form of piston but if desired, the cylinder itself may be formed of a material having fiber as a component part thereof.

In actual practice, however, I have used the metallic cylinder with a novel form of piston and have found V613 sults throughout extende formance.

In order to fully appreciate the invention, reference should be'had to the following description in connection with the accompanyingrdrawings, in which i 1 is a fragmentary, longitudinal, sectiona view through an air compressor to which my invention is applied.

Fi 2 is an enlarge, longitudinal sectiona view through the piston.

Fig. 3 is a sectional view through one form of material of which the piston is made.

Fi 2 is an exaggerated sectional view showmg the alternate layers of the material and fiber; the rings 1 designate'the material which alternates with the her or fabriclayers 2. The material 1 is preferably a nonmetallic substance, such as bakelite. or micarata and the fiber is preferably arranged in sheets alternating with the rings 1. The ends of the fibers are exposed to the outer peripheral surface of the rin 1 so that-they will come into contact with the cylinder 3 as thepiston reciprocates therein.

The fiber sheets may be arranged as shown prefer to provide a metallic' in Fig. 2 or they may be arrangedas shown in Fig. 3. The fiber may also be embedded in any appropriate manner in the material 1.

The piston may be provided withcircumferential grooves 4, intermediate its ends but preferably near the compression end of the piston. contain lubricant, such as oil, and during the reciprocation of the piston in the cylinder, the oil will be spread against the surface of the cylinder; part of it will initially be absorbed by capillary attraction set up by the fiber so that the fiber will become iin pregnated with the lubricant, thereby holding a reserve supply of lubricant to be redistributed over the cylinder, making the piston entirely self-lubricating.

The oil grooves will efiicienctly seal the 7 cylinder, being assisted by the fibers and by the fact that the piston will be non-scoring since its consistency is such that it will not cut the inner surface of the cylinder. This I have demonstrated in actual practice.

As above-stated, the cylinder may, under certain conditions, be formed of a material having fiber embedded therein but ordinarily The grooves are adapted to I prefer to construct the engine with a cylinder of metal and have the piston contain the fiber. and bakelite as being the best materials because they particularly lend themselves to a piston construction. I do not wish to be fiber being exposed to the surface of the piston, and circumferential, lubricant-containing grooves in the periphery of the piston to supply lubricant to the fiber.

2. A non-metallic piston having-fiber as a component part thereof, the ends of the fiber being exposed to the surface of the piston, and lubricant-containing recesses in the:

piston to supply lubricant to the fiber. In testimony whereof I aflix my signature.

- CHLES W. HACK.

I have recommended micarta, 

